The railroad industry has long been plagued by the problem of loosening of rails from wood cross ties along the railway roadbeds. Although the rails are secured to the cross ties by driving headed spikes into the cross ties to contact the flanges of the rails, the spikes nevertheless may be loosened as a result of vertical forces caused by wave-like motions of the rails produced as engines and loaded cars move along the rails. Further, lateral wheel forces produced on the tops of the rails as a result of side-to-side swaying of the moving locomotive and its cars and centrifugal forces as the locomotive and cars traverse curves of the railway tend to cause rails to tilt or rock about their flanged bases. The wave-like motion and lateral forces due to swaying, and various early attempts to solve the problem are set forth in greater detail in my U.S. Pat. No. 3,964,680, filed Feb. 3, 1975, issued June 22, 1976, and incorporated herein by reference.
To alleviate the problem of loosening of spikes, various spike retainers have been utilized to reliably retain spikes in the wood cross ties despite the tendency of the above described forces to loosen spikes. The above mentioned patent discloses one such railroad spike retainer.
Railroad rails are ordinarily positioned on tie plates, which are thick rectangular steel plates having a width considerably greater than the width of the flanged base of the rails. Generally, grooves are provided in tie plates for snugly accommodating the flanged bases of the rails. Apertures are provided in the tie plates adjacent the flanged bases of the rails so that spikes can be driven through such apertures into the cross ties in such a manner that heads of the spikes securely engage the flanged bases. As long as the spikes remain tightly engaged in the cross ties, both the rails and the tie plates remain securely attached to the cross ties.
A railroad spike system referred to as the "PLATELOC" system, manufactured by True Temper Corp. of Cleveland, Ohio, provides a clamping device having a sharp lower lip which is forced into a wood cross tie immediately beneath the bottom surface of a tie plate. The clamping device also includes an upper lip which extends over the flanged base of a rail supported by the tie plate. The PLATELOC clamping device is inserted through an aperture in the tie plate immediately adjacent the flanged base of the rail. A specially designed spike is forcibly inserted through the aperture, forcing the clamping device against the tie plate and forcing the lower lip into the cross tie immediately below the bottom surface of the tie plate. The clamping device tends to clamp the flanged base and the tie plate together, thereby tending to prevent lateral tilting or rocking of the rail on the tie plate even if the spike becomes somewhat loosened (because the tie plate has a much broader base than the flanged base of the rail). However, the PLATELOC device is inconvenient to install, since a special operation is required to properly place the clamping device in the tie plate aperture before driving the spike through that aperture, and more importantly, it cannot be used with presently available spike retainers. This is a serious shortcoming, since presently available spike retainers have been proven to greatly increase the reliability with which spikes are retained in wooden cross ties. Yet another shortcoming of the PLATELOC system is that smaller spikes having only approximately half of the surface area of conventional spikes must be utilized, since tie plate apertures are of a standard size. Consequently, the capability of the PLATELOC spikes to grip the walls of the holes in wood cross ties is believed to be substantially reduced. The PLATELOC system therefore is believed to be unduly subject to loosening of spikes.
Accordingly, it is an object of the invention to provide a system for avoiding or reducing the tendency of railroad rails to tilt as a result of lateral wheel forces produced by locomotives and cars traversing a railway.
Another object of the invention is to provide an improved system for connecting rails to cross ties wherein spikes are reliably retained in wooden cross ties and wherein flanged bases of rails are securely clamped to underlying tie plates.
Another rail fastening device, known as a gauge LOCKSPIKE includes a spike shaped somewhat like a hairpin, wherein the end portions of the legs of the fastener are parallel, but are separated at their upper ends so that compression on the separated portions of the legs by the hole in the base plate creates a tendency for the ends of the legs to separate in a hole in the wooden cross tie, resulting in increased gripping of the wooden cross tie. However, the LOCKSPIKE device is not suitable for use with spike retainers, and does not provide rigid clamping between the base plate of a rail and the base plate. Therefore, gripping of the wooden cross tie tends to be reduced as the spike becomes loosened due to the above mentioned forces.
Yet another object of the invention is to provide a rail fastening system wherein clamping between a flanged base of a rail and a supporting tie plate is not substantially reduced as a result of loosening of a spike.